Brown geologists are spending three months in the rugged Dry Valleys (above) of Antarctica, a region of freeze-dried ridges
and slopes. To move camp, they need to call for a helicopter.
Credit: Michael Wyatt/Brown University

Hunting climate clues in Antarctica

Brown geologists are braving subfreezing temperatures for three months to visit “the oldest ice on Earth.” Their goal? A better understanding of our planet’s climate history – and current conditions on Mars.

A team of Brown University geologists is going to extremes to
learn about past climate on Earth and the present climate on Mars.

Seven faculty, postdoctoral researchers, and graduate students
are in Antarctica to collect rock samples and study a region that holds climate
clues dating back millions of years. For three months, the geologists will toil
in the rugged Antarctic Dry Valleys, a region of freeze-dried gullies, ridges,
and slopes. To move camp, they’ll need to call for a helicopter. For
nourishment, they’ll rely on frozen food, crackers, and granola bars. They will
melt snow for drinking water and cooking.

And they’ll shiver a lot, burning calories as they try to
stay warm against temperatures that during their summertime stay won’t stray
above freezing. “I expect to be about 30 pounds lighter when I get back,”
Michael Wyatt, assistant professor in geological sciences and one of two
faculty on the trip, said without a hint of amusement.

Satellite view of the Dry Valleys of AntarcticaLocated in the central Trans Antarctic Mountains, the
Antarctic Dry Valleys (also called the McMurdo Dry Valleys) lie
between the East Antarctic Ice Sheet and the Ross Sea. (See map, below.) The valleys, each about
50 miles long and nine miles wide, are mostly ice free, a fortunate turn of
geological events considering that 98 percent of Antarctica is permanently
covered with snow or ice.

The expedition is funded through a $470,000 grant from the
National Science Foundation. The money covered research in Antarctica during
the 2008–2009 austral summer season as well as this trip. Team members will
detail their experiences in periodic dispatches from their camps, which will
include photos and other graphics.

Taken collectively, the valleys comprise a unique ecosystem
that holds clues to very important questions, said James “Jim” Head III ’69
Ph.D., professor of geological sciences, who is making his fourth trip to the
continent. For one, the valleys have entombed volcanic ash up to 8 million
years old within cracks in the terrain that geologist call polygons. The ash, which has fallen periodically through those millions of years, has remained essentially unchanged ever since, making it an ideal source to date periods in Earth’s climate history.

“It’s probably the oldest ice on Earth,” said Head, who
along with Boston University geologist David Marchant wrote a paper two years
ago detailing the Dry Valley’s unique characteristics.

Maps show the site being explored by Brown geologists during the Antarctic summer.
Brown postdoctoral researcher Gareth Morgan and Brandon
Boldt, a graduate student studying with Head, are part of a Boston University
team that will plunge drills up to 40 meters deep in debris-covered glaciers to
extract ice cores they hope will yield information about past atmospheric gases
such as carbon dioxide, temperature and the types of life that existed at
various geologic intervals. The group also hopes to find evidence for ancient
bacteria and other signs of past life.

“This is a challenging activity,
but it may help us to better understand our own planet’s climate history,”
Morgan wrote days before he left for Antarctica.

Another group including Head, Brown research analyst James
Dickson, and Laura Kerber, one of Head’s graduate students, are studying the
geological processes that formed the Dry Valleys. Moving inland from the coast,
scientists have identified three distinct climatic zones in the valleys. Each
of these “microclimates” has distinct signatures that can be interpreted by
studying how rocks have been altered by wind, temperature, water, and chemical
reactions.

The researchers will gather rock samples at dozens of
locations, marking precisely the spot at which each sample is gathered. By
analyzing the mineral composition of the rocks, the scientists can “see how
they’ve changed, how they’ve been altered in these different climate zones,”
Wyatt explained.

A windswept view of a Dry Valley.
In addition to painting a picture of Earth’s past, the
Antarctic rocks will present a vivid picture of Mars’s present. Scientists
like to say that Antarctica is the closest that one can get to Mars’s
environment. The climates are similar – hyper-arid, windy, and frigid. Just as
important, Antarctica has landforms, such as polygons, gullies, and
debris-covered glaciers that are strikingly similar to regions on Mars. So, the
thinking goes, by studying rocks from the Dry Valleys, scientists can get
insights into the geology of Mars – and help answer the elusive questions of how
much water exists on Mars and what it has been doing there.

“If we’re able to map the minerals here and compare it to
minerals we also see on Mars (through data gathered from orbiters and landers)
… we are setting a minimum limit for how much water you need to produce the
same alterations that we see in the Dry Valleys,” said Wyatt, who will team
with graduate student Mark Salvatore on that aspect of the research.

“It’s totally exciting,” added Head. “You can sit in your office and look all day at images of Mars. And you try essentially to place yourself on the surface of Mars. But there is no substitute for going to this Mars-like place on Earth and having an immersive experience.”

The Brown research team will file periodic dispatches and photographs from the Antarctic to be published on Today at Brown.